I finished up the bodywork and prep on the driver's side trunk drop-off. In order to reproduce the original heavy body shutz sound deadener I used a couple cans of spray-on bedliner instead of undercoating. It worked very well as long as you spray it from at least a foot away to allow it to hit the panel in a dryer state. You don't want to spray it on wet. It will look too smooth at a minimum and will all "landslide" off the panel if it is too wet.
Here is the original drop-off from my 1972 Trans Am that was built a week before the Formula at Norwood:
And the finished result:
It's a helluva lot better looking than the way it came: